4.5 makes Fantom occluding on hair much easier

Back on the old forums I Had a topic about using Fantom shielding which is a a mesh with the Ubersurface shader on it to cause occlusion shading on transparency heavy objects(such as hair) and there surroundings.

The Geometry shell option in 4.5 allows you to create a duplicate of the original hair mesh slightly offset which you can use providing superior results.

Basically this lets you render hair with occlusion effects significantly faster (6x +) and with the geometry shell its now faster to set up.

Heres a quick render

Comments

Back on the old forums I Had a topic about using Fantom shielding which is a a mesh with the Ubersurface shader on it to cause occlusion shading on transparency heavy objects(such as hair) and there surroundings.

The Geometry shell option in 4.5 allows you to create a duplicate of the original hair mesh slightly offset which you can use providing superior results.

Basically this lets you render hair with occlusion effects significantly faster (6x +) and with the geometry shell its now faster to set up.

Heres a quick render

Beautiful render, the hair looks stunning. Would you be willing to write a few pointers on how to do this?

First of all the original Hair needs to have its materials converted to use a shader that you can turn off the ocllusion. In my render im using the elite ponytail hair which already comes with ubersurface shader materials.

Once materials are converted set the occlusion of all surfaces to Off, in some cases better results can be achieved by leaving a skull cap material on.

Create a Geometry shell of the hair, some hairs are multiple objects create a geometry shell of each part.

Select the geometry shell and open up the surfaces, Convert them to Ubersurface shader set opacity to @30% on each surface except the skiull cap which you can make 0%

Receive shadows and Raytracing options should me off and occlusion and Fantom should be on for all of the geometry shell surfaces.

Do a test render and adjust the opacity setting to taste and in some cases increasing the specular values on the original hair gets good results.

First of all the original Hair needs to have its materials converted to use a shader that you can turn off the ocllusion. In my render im using the elite ponytail hair which already comes with ubersurface shader materials.

Once materials are converted set the occlusion of all surfaces to Off, in some cases better results can be achieved by leaving a skull cap material on.

Create a Geometry shell of the hair, some hairs are multiple objects create a geometry shell of each part.

Select the geometry shell and open up the surfaces, Convert them to Ubersurface shader set opacity to @30% on each surface except the skiull cap which you can make 0%

Receive shadows and Raytracing options should me off and occlusion and Fantom should be on for all of the geometry shell surfaces.

Do a test render and adjust the opacity setting to taste and in some cases increasing the specular values on the original hair gets good results.

Any other questions just ask.

Thanks for the info...I will hopefully have time this weekend to have a play.

How did you keep the blond hair so lovely and light colored? I tried following the instructions, but when I added the geometry shell. my blond hair came out much darker than the original color. I must be doing something wrong. I even lowered the opacity of the hair parts of the geometry shell to 15% and the cap at 0%, which only helped a little.

How did you keep the blond hair so lovely and light colored? I tried following the instructions, but when I added the geometry shell. my blond hair came out much darker than the original color. I must be doing something wrong. I even lowered the opacity of the hair parts of the geometry shell to 15% and the cap at 0%, which only helped a little.

Most of the detail comes from the specular being increased but it also depends on your occlusion settings.

Im assuming that occlusion is now disabled on the hiar itself if so you can brighten the diffuse(assuming it isnt white) or increase the specular settings.

Specualr lights also have a dramatic effect on hair that has detailed specular/bump maps like the Elite ponytail.

If you need some specific help feel free to post light/material settings.

Thanks for the tips. You had mentioned specular in your instructions, but I hadn't tried that. I looked at my hair material settings and saw that specular was black. This is an older hair product that doesn't even have DS settings, I think. So, I changed the specular to white at 100% on the hair and set the geometry shell opacity back to 30%. It is looking better now. (The diffuse was already white, so no change made there.)

Should the geometry shell have specular on? Should the geometry shell have Cast Shadows set to ON? These settings are on by default in my shell. Should I change them?

These are the setting I have:Hair:
Fantom OFF
Raytrace ON
Accept Shadows ON
Occlusion OFF
Opacity 100%
Specular white 100%

For the picture at the top the shell has cast shadows to "off" and im using 1 specular distant (shadow mapped) and a uber spotlight (shadow mapped) low intesity with the shadow intensity @300%.

The aim of the shell is to provide occlusion on the hair and its surroundings similar to what would normally be found without having to make time intensive calculations because of the opacity maps.

Shadow maps(when the renderer doesnt throw a wobbler) can be good quality soft shadow and doesnt take long to calculate on the hair.

You can use raytraced shadows but for this you need to have the shell cast shadows but set the hair so it doesnt receive shadows. This obviously won't work if you require a shadow to fall on the hair from elsewhere. Using raytraced shadows this way "can" be quicker on mid to low shadow sample settings as higher settings are only needed when the shadow falls some distance from the object and you won't need the time to calculate the shadow maps.

Your instructions are helping me understand how this works, but I still have a lot left to learn about all these settings and what each one does. I've pretty much avoided deep shadow maps lately, because almost every render is destroyed by the sparkly red and blue squares. I'd hoped that would be fixed in 4.5, but for me, it seems much worse.

I did three renders to compare. All three used UE2 Occlusion with soft shadows. (I wonder in what order DAZ will show the attached pictures???)

1) DAZ Default shader on hair, raytraced distant light, no geometry shell (This is the baseline without fantom occlusion).
Observations:
Shadows of hair strands show on face and hair layers are clearly visible with top layer shadowing lower layer.
2) Geometry shell, raytraced distant light, hair cast shadow ON, shell cast shadow ON, Hair accept shadow OFF
Observations:
Shadows of hair strands show on face (because hair is casting shadow with raytracing using hair transmap?)
Hair layers are not visible, because hair is not accepting shadows, so top layer does not shade lower layer.Is it correct to have both the hair and the shell casting shadows?
3) Geometry shell, shadow mapped distant light, hair cast shadow ON, shell cast shadow OFF, Hair accept shadow ON
Observations:
Shadows of hair strands do not show on face (because shadow map does not use hair transmap?)
Hair layers are visible because hair is accepting shadows
Render is pock marked with red and blue rendering errors >:(

So, am I homing in a correct combination of settings to get the best out of fantom occluding? I appreciate any observations you make.
Thanks.

DSM does take transmaps into account. You just need to set a higher shadow samples number in your Render Settings. Go up all the way to 64, I think that's the limit hardcoded in the Studio UI right now (there are ways to bypass the limit, but it would warrant a topic of its own). It will not slow you down any noticeably, and you should see more shadow definition. You could also dial shadow softness down if you're using it, it doesn't seem to add much to DSM.

DSM does take transmaps into account. You just need to set a higher shadow samples number in your Render Settings. Go up all the way to 64, I think that's the limit hardcoded in the Studio UI right now (there are ways to bypass the limit, but it would warrant a topic of its own). It will not slow you down any noticeably, and you should see more shadow definition. You could also dial shadow softness down if you're using it, it doesn't seem to add much to DSM.
Thanks for that suggestion. I will give it a try and see how it works.

If I can find out how to distribute the material presets for the hair and geometry shell then youll have a good reference.

Anyone help with that?

Like Mustakettu85 said you can save it as a material preset but it could be better to save in dsa preset so that people not having DS4.5 could use it too

You just have to select the figure you want to save then Save as->Deprecated->Material preset. Check "Record all" then give it a name somewhere you can find it easily. It should create a dsa file with the associated png